Aresearch firm supplies manufacturers with estimates of the sales of their products from samples of stores. marketing managers often look at the sales estimates and ignore sampling error. an srs of 50 stores this month shows mean sales of 41 units of a particular appliance with a standard deviation of 11 units. during the same month last year, an srs of 52 stores gave mean sales of 38 units of the same appliances with a standard deviation of 13 units. an increase from 38 to 41 is a rise of 7.9 % . the marketing manager is happy because sales are up 7.9 % . (a) give a 95 % confidence interval for the difference in mean number of units of the appliance sold at all retail stores. (enter your answer rounded to three decimal places.) lower interval: upper interval:

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3

inverse property is the answer

step-by-step explanation:

y=sec x is the correct answer

~batmans wife dun dun